Radiation detecting apparatus, radiographic image capturing system, and radiographic image capturing method

ABSTRACT

An electronic cassette in a radiographic image capturing system includes a radiation detector for detecting radiation applied from an image capturing apparatus and transmitted through a patient, a contactless power receiver for receiving electric power supplied contactlessly from a power feeder and supplying the electric power to a battery, an A/D converter for performing an A/D conversion to convert analog radiographic image information generated based on the radiation applied to the radiation detector into digital radiographic image information, an end-of-A/D-conversion determining unit for determining whether the A/D conversion is finished or not, and a charging controller for stopping the power feeder from supplying electric power contactlessly after the image capturing apparatus has started capturing images until the end-of-A/D-conversion determining unit judges that the A/D conversion is finished.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromPatent Applications No. 2008-316529 filed on Dec. 12, 2008 and No.2009-271507 filed on Nov. 30, 2009, in the Japan Patent Office, of whichthe contents are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a radiation detecting apparatus havinga radiation detector for detecting radiation which has passed through asubject and a contactless power receiver, a radiographic image capturingsystem having a contactless power feeder for contactlessly supplyingelectric power to such a radiation detecting apparatus, and aradiographic image capturing method.

2. Description of the Related Art

In the medical field, there have widely been used radiographic imagecapturing apparatus, which apply radiation to a subject and guide theradiation that has passed through the subject to a radiation conversionpanel, which captures a radiographic image from the radiation. Knownforms of the radiation conversion panel include a conventional radiationfilm for recording a radiographic image by way of exposure, and astimulable phosphor panel for storing radiation energy representing aradiographic image in a phosphor and reproducing the radiographic imageas stimulated light by applying stimulating light to the phosphor. Theradiation film with the recorded radiographic image is supplied to adeveloping device to develop the radiographic image, or the stimulablephosphor panel is supplied to a reading device to read the radiographicimage as a visible image.

In the operating room or the like, it is necessary to read and display arecorded radiographic image immediately from a radiation conversionpanel after the radiographic image has been captured for the purpose ofquickly and appropriately treating the patient. Patients such asinfants, children, aged people, or those who cannot stand themselves fora long time due to illness or injuries also need to be imaged quickly.As a radiation conversion panel which meets such a requirement, therehas been developed a radiation detector having a solid-state detectorfor converting radiation directly into electric signals or convertingradiation into visible light with a scintillator and then converting thevisible light into electric signals to read a detected radiographicimage.

Japanese Laid-Open Patent Publication No. 2008-170315 discloses aradiation detecting apparatus (electronic cassette) having a function totransmit radiographic image information produced by a radiation detectorto an image processor or the like via a wireless transmission system.The electronic cassette incorporates a battery therein. For charging thebattery, the electronic cassette is mounted on a separate cradle havinga contactless battery charger. The battery is contactlessly (wirelessly)charged by the contactless battery charger while the electronic cassetteis being mounted on the cradle.

According to the radiation detecting apparatus disclosed in JapaneseLaid-Open Patent Publication No. 2008-170315, when the remaining powerlevel of the battery runs low after the radiation detecting apparatushas been used to capture a plurality of radiographic images of a patientduring a surgical operation on the patient, it is necessary to removethe electronic cassette from under the patient, bring the electroniccassette to the cradle, and charge the battery in the electroniccassette that is mounted on the cradle. However, such a charging processis troublesome and possibly tends to make the surgical operationtime-consuming and be burdensome to the patient.

Another problem is that if the battery is contactlessly charged by thecontactless battery charger while radiographic image informationproduced by a radiation detector incorporated in the electronic cassetteis being converted from an analog signal to a digital signal during thesurgical operation, noise caused by magnetic fluxes used for thecontactless power charging is liable to adversely affect theradiographic image information, particularly the analog signal prior tobeing converted into the digital signal. As a result, it is highlypossible for the radiation detecting apparatus to fail to acquirehigh-quality radiographic images.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a radiationdetecting apparatus, a radiographic image capturing system, and aradiographic image capturing method which make it possible to supplyelectric power to the radiation detecting apparatus with ease and alsoto acquire high-quality radiographic images.

A radiation detecting apparatus according to the present inventioncomprises a radiation detector for detecting radiation applied from anexternal image capturing apparatus and transmitted through a subject, acontactless power receiver for receiving electric power suppliedcontactlessly from an external contactless power feeder and supplyingthe received electric power to a power supply, an A/D converter forperforming an A/D conversion to convert analog radiographic imageinformation which has been generated based on the radiation applied tothe radiation detector, into digital radiographic image information, anend-of-A/D-conversion determining unit for determining whether the A/Dconversion is finished or not, and a charging controller for stoppingthe contactless power feeder from supplying electric power contactlesslyafter the external image capturing apparatus has started to capture aradiographic image until the end-of-A/D-conversion determining unitjudges that the A/D conversion is finished.

A radiographic image capturing system according to the present inventioncomprises an image capturing apparatus for applying radiation to asubject, a radiation detecting apparatus including a radiation detectorfor detecting the radiation transmitted through the subject, an A/Dconverter for performing an A/D conversion to convert analogradiographic image information which has been generated based on theradiation applied to the radiation detector, into digital radiographicimage information, and a power supply for supplying electric power tothe radiation detector, a contactless power feeder disposed in theradiation detecting apparatus, for supplying electric powercontactlessly to a contactless power receiver which supplies electricpower to the power supply, a controller for controlling the imagecapturing apparatus, the radiation detecting apparatus, and thecontactless power feeder, an end-of-A/D-conversion determining unit fordetermining whether the A/D conversion is finished or not, and acharging controller for stopping the contactless power feeder fromsupplying electric power contactlessly after the image capturingapparatus has started to capture a radiographic image until theend-of-A/D-conversion determining unit judges that the A/D conversion isfinished.

With the above arrangement, while the radiation detecting apparatus withthe radiation detector for detecting the radiation, e.g., an electroniccassette, is being held in a given image capturing position, thecontactless power feeder can supply electric power to the radiationdetecting apparatus with ease. Additionally, the end-of-A/D-conversiondetermining unit and the charging controller are provided, and after theimage capturing apparatus has started capturing a radiographic image ofthe subject until the A/D conversion is finished, the contactless powerfeeder stops supplying electric power contactlessly to the contactlesspower receiver. Therefore, since the contactless power feeding isinhibited from the start of image-capturing at least until theconversion of the analog radiographic image information detected by theradiation detector into the digital radiographic image information iscompleted, the analog radiographic image information which issusceptible to noise is prevented from being adversely affected by noisewhich is caused by the contactless power feeding from the contactlesspower feeder. Thus, it is possible to acquire radiation images of highquality. After the A/D conversion, i.e., at a time when the radiographicimage information is relatively less susceptible to noise, theradiographic image capturing system can quickly start supplying electricpower to the power supply. Even when the remaining power level of thepower supply has been greatly reduced by a previous image capturingprocess, the power supply can be quickly charged after the previousimage capturing process and made ready for a next image capturingprocess.

In order to reliably stop the contactless power feeder from supplyingelectric power contactlessly to the contactless power receiver from thestart of image capturing until the end of the A/D conversion, thecharging controller may generate a feeding inhibition signal to inhibitthe contactless power feeder from supplying electric power contactlesslybefore the external image capturing apparatus starts to capture aradiographic image, or the charging controller may generate a feedingpermission signal to permit the contactless power feeder to supplyelectric power contactlessly if the end-of-A/D-conversion determiningunit judges that the A/D conversion is finished

The radiation detecting apparatus may further comprise an image memoryfor storing the digital radiographic image information converted by theA/D converter, and the end-of-A/D-conversion determining unit may judgethat the A/D conversion is finished when the digital radiographic imageinformation is stored in the image memory. With this arrangement, theradiographic image information is effectively prevented from beingadversely affected by noise while it is being transferred to the imagememory, and hence from being corrupted. Consequently, the radiographicimage capturing system can acquire radiographic images of high quality.

There may be further provided an image capturing controller forgenerating an image capturing permission signal to permit the imagecapturing apparatus to capture a radiographic image of the subject whenthe charging controller generates the feeding inhibition signal. Theimage capturing controller makes it possible to more reliably inhibitthe contactless power feeder from supplying electric power contactlesslyduring the image capturing process.

The radiographic image capturing system may be connected to aninformation management system for storing the number of times that thesubject is to be imaged, and the end-of-A/D-conversion determining unitmay determine whether the A/D conversion is finished or not after asmany radiographic images of the subject as the number of times that thesubject is to be imaged which is stored in the information managementsystem have been captured. With this arrangement, the contactless powerfeeder can start supplying electric power contactlessly reliably afterall the radiographic images of the subject have been captured and theA/D conversion of all the radiographic image information is completed.

The charging controller may generate the feeding permission signal whenthe image capturing apparatus stops applying the radiation and when theend-of-A/D-conversion determining unit judges that the A/D conversion isfinished. With this arrangement, even if information about the number oftimes that the subject is to be imaged cannot be obtained from a networkor the like, the end of the capturing of the desired number ofradiographic images can be judged from the stop of the application ofthe radiation, e.g., the turning-off of an image capturing switch.Accordingly, the radiographic image capturing system can start supplyingelectric power contactlessly to the power supply reliably after thecapturing of all radiographic images and the A/D conversion of allradiographic image information are completed.

The charging controller may generate the feeding permission signal uponelapse of a given time after the end-of-A/D-conversion determining unithas judged that the A/D conversion is finished. With this arrangement,the completion of the A/D conversion and the time required for thetransfer of the digital radiographic image information to the imagememory can be secured, and noise is effectively prevented from adverselyaffecting the digital radiographic image information being transferredto the image memory.

The charging controller may generate the feeding permission signal uponelapse of a given time after the image capturing apparatus has startedapplying the radiation. With this arrangement, the time from the startof the application of the radiation until the completion of the A/Dconversion and the time required for the transfer of the digitalradiographic image information to the image memory can be secured, andthereafter the feeding permission signal can be generated. Theend-of-A/D-conversion determining unit may judge that the A/D conversionhas been finished in view of the given time from the start of theapplication of the radiation. In other words, the function of theend-of-A/D-conversion determining unit may be integrated into thecharging controller.

According to the present invention, there is also provided a method ofcapturing a radiographic image of a subject by applying radiation to thesubject, detecting the radiation with a radiation detector of aradiation detecting apparatus, and converting the detected radiationinto radiographic image information with the radiation detector,comprising the steps of supplying electric power contactlessly to apower supply of the radiation detecting apparatus, and stoppingsupplying electric power contactlessly to the power supply afterimage-capturing by the radiation has been started at least until an A/Dconversion of the radiographic image information detected by theradiation detector is finished.

The above method is effective to prevent noise generated by electricpower supplied contactlessly from a contactless power feeder fromadversely affecting captured radiographic images by starting to supplyelectric power contactlessly at least after the completion of the A/Dconversion of the acquired radiographic image information. Therefore, itis possible to acquire radiographic images of high quality.

The above and other objects, features, and advantages of the presentinvention will become more apparent from the following description whentaken in conjunction with the accompanying drawings in which preferredembodiments of the present invention are shown by way of illustrativeexample.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an operating room incorporating aradiographic image capturing system according to a first embodiment ofthe present invention;

FIG. 2 is a perspective view, partly cut away, showing internalstructural details of an electronic cassette used in the radiographicimage capturing system shown in FIG. 1;

FIG. 3 is a block diagram of a circuit arrangement of a radiationdetector in the electronic cassette shown in FIG. 2;

FIG. 4 is a block diagram of the radiographic image capturing systemshown in FIG. 1;

FIG. 5 is a block diagram of the radiographic image capturing system,showing structural details of the electronic cassette shown in FIG. 4;

FIG. 6 is a flowchart of an image capturing, sequence of theradiographic image capturing system shown in FIG. 4;

FIG. 7 is a block diagram of a radiographic image capturing systemaccording to a second embodiment of the present invention;

FIG. 8 is a flowchart of a first image capturing sequence of theradiographic image capturing system shown in FIG. 7;

FIG. 9 is a flowchart of a second image capturing sequence of theradiographic image capturing system shown in FIG. 7;

FIG. 10 is a flowchart of a third image capturing sequence of theradiographic image capturing system shown in FIG. 7;

FIG. 11 is a block diagram of a radiographic image capturing systemaccording to a first modification of the radiographic image capturingsystem shown in FIG. 4;

FIG. 12 is a perspective view of another electronic cassette;

FIG. 13 is a perspective view of a cradle for charging a battery in theelectronic cassette;

FIG. 14 is a side elevational view, partly in block form, of aradiographic image capturing system according to a second modificationof the radiographic image capturing system shown in FIG. 4;

FIG. 15 is a side elevational view, partly in block form and crosssection, of a radiographic image capturing system according to a thirdmodification of the radiographic image capturing system shown in FIG. 4;

FIG. 16 is a schematic view of a radiographic image capturing systemaccording to a fourth modification of the radiographic image capturingsystem shown in FIG. 4; and

FIG. 17 is a schematic view of a radiographic image capturing systemaccording to a fifth modification of the radiographic image capturingsystem shown in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Like or corresponding parts are denoted by like or correspondingreference characters throughout views.

Radiographic image capturing systems and radiographic image capturingmethods according to preferred embodiments of the present invention, inreference to radiation detecting apparatus used in the radiographicimage capturing systems, will be described in detail below withreference to the accompanying drawings.

As shown in FIG. 1, an operating room 12 houses therein a radiographicimage capturing system 10 (hereinafter also referred to as “imagecapturing system 10”) according to a first embodiment of the presentinvention. The operating room 12 houses, in addition to the radiographicimage capturing system 10, a surgical table or bed 16 for a patient 14to lie thereon, and an instrument table 20 disposed on one side of thesurgical table 16 for placing thereon various tools and instruments tobe used by a surgeon 18 for operating the patient 14. The surgical table16 is surrounded by various apparatus required for surgical operations,including an anesthesia apparatus, an aspirator, an electrocardiograph,a blood pressure monitor, etc (not shown).

The image capturing system 10 includes an image capturing apparatus(radiation applying apparatus) 22 for irradiating the patient 14 as asubject with radiation X at a dose according to image capturingconditions, an electronic cassette (radiation detecting apparatus) 24housing therein a radiation detector 40 (see FIG. 2) for detecting theradiation X that has passed through the patient 14, a power feeder(contactless power feeder, wireless power feeder) 25 for supplyingelectric power wirelessly (contactlessly) to a battery 44 (see FIG. 2)housed in the electronic cassette 24, a display device 26 for displayinga radiographic image based on the radiation X that has been detected bythe radiation detector 40, and a console (controller) 28 for generallycontrolling the image capturing system 10. The image capturing apparatus22, the electronic cassette 24, the power feeder 25, the display device26, and the console 28 send and receive signals by way of UWB (UltraWide Band) wireless communications indicated by the broken lines.

Since the power feeder 25 and the electronic cassette 24 are out ofcontact with each other, a contactless power feeding technique forfeeding power contactlessly (wirelessly) is adopted as a technique forfeeding power to (the battery 44 of) the electronic cassette 24 by thepower feeder 25, as described above.

Specifically, the contactless power feeding technique includes (1) amicrowave power feeding technique in which the power feeder 25 feedspower to the electronic cassette 24 using an electromagnetic wave in themicrowave band, (2) an electromagnetic induction power feeding techniquein which the power feeder 25 feeds power to the electronic cassette 24by electromagnetic induction with the coil of the power feeder 25 beingin proximity to the coil of the electronic cassette 24, and (3) aresonance power feeding technique in which the power feeder 25 feedspower to the electronic cassette 24 using electromagnetic resonancebetween the power feeder 25 and the electronic cassette 24.

Also, the above resonance power feeding technique (3) includes amagnetic resonance power feeding technique. In the magnetic resonancepower feeding technique, the coils of the power feeder 25 and theelectronic cassette 24 are adjusted to have substantially the sameresonant frequency, and the coil of the power feeder 25 on the sendingside generates electromagnetic field caused by high-frequency electricpower in a given space of the operating room 12, while the coil of theelectronic cassette 24 on the receiving side is placed in the generatedelectromagnetic field, whereby the coil of the electronic cassette 24can receive the high-frequency electric power.

Incidentally, the contactless power feeding technique for feeding powerto the electronic cassette 24 by the power feeder 25 (microwave type,electromagnetic induction type, resonance type, magnetic resonance type)can adopt a conventional contactless power feeding technique.

Hereinafter, if not otherwise specified, the power feeder 25 feeds powerto the battery 44 of the electronic cassette 24 using a magneticresonance power feeding technique.

The image capturing apparatus 22 is coupled to a universal arm 30extending from the ceiling of the operating room 12 so as to be movableto a desired position for capturing an image of a desired area of thepatient 14 and also to be retractable to a position out of the way whilethe surgeon 18 is performing a surgical operation on the patient 14.Similarly, the power feeder 25 is coupled to a universal arm 31 so as tobe movable to a desired position depending on the location of theelectronic cassette 24. The display device 26 is coupled to a universalarm 32 so as to be movable to a position where the surgeon 18 can easilyconfirm a captured radiographic image displayed on the display device26. The universal arms 30, 31, 32 may alternatively be mounted on awall, a floor, or a movable cart. The power feeder 25 and the displaydevice 26 may alternatively be fixed to the ceiling, a wall, or a floorrather than being supported on the universal arms. The power feeder 25should preferably be positioned horizontally laterally of the radiationdetecting apparatus (the electronic cassette 24) (see FIGS. 1 and 14) oron the bottom side of the radiation detecting apparatus (see FIG. 15) sothat a magnetic field M (electromagnetic field due to high-frequencyelectric power) applied from the power feeder 25 to the radiationdetecting apparatus will be kept out of direct interference with thepatient 14.

FIG. 2 shows in perspective internal structural details of theelectronic cassette 24. As shown in FIG. 2, the electronic cassette 24has a box-shaped casing 34 made of a material permeable to the radiationX. The casing 34 houses therein a grid 38 for removing scattered rays ofthe radiation X from the patient 14, a radiation detector (radiationconversion panel) 40 for detecting the radiation X that has passedthrough the patient 14, and a lead plate 42 for absorbing back scatteredrays of the radiation X, which are successively arranged in the ordernamed from a surface 36 of the casing 34 which is irradiated with theradiation X. The irradiated surface 36 of the casing 34 may beconstructed as the grid 38.

The casing 34 also houses therein a battery 44 serving as a power supplyof the electronic cassette 24, a cassette controller 46 for energizingthe radiation detector 40 with electric power supplied from the battery44, and a transceiver 48 for sending and receiving signals including theinformation of the radiation X (radiographic image information) detectedby the radiation detector 40, to and from the console 28 by wirelesscommunications. A shield plate of lead or the like should preferably beplaced over the side surfaces of the battery 44, the cassette controller46, and the transceiver 48 under the irradiated surface 36 of the casing34 to protect the battery 44, the cassette controller 46, and thetransceiver 48 against damage which would otherwise be caused ifirradiated with the radiation X. The casing 34 also houses therein awireless power receiver (contactless power receiver) 49 for receivingthe magnetic field (magnetic fluxes) M converted from electric energy(high-frequency electric power) and applied contactlessly (wirelessly)by the power feeder 25, and converting the magnetic field M back intoelectric energy.

FIG. 3 shows in block form a circuit arrangement of the radiationdetector 40. As shown in FIG. 3, the radiation detector 40 comprises anarray of thin-film transistors (TFTs) 52 arranged in rows and columns, aphotoelectric conversion layer 51 made of a material such as amorphousselenium (a-Se) for generating electric charges upon detection of theradiation X, the photoelectric conversion layer 51 being disposed overthe array of TFTs 52, and an array of storage capacitors (storagedevices) 53 connected to the photoelectric conversion layer 51. When theradiation X is applied to the radiation detector 40, the photoelectricconversion layer 51 generates electric charges, and the storagecapacitors 53 store the generated electric charges. Then, the TFTs 52are turned on along each row at a time to read the electric charges fromthe storage capacitors 53 as an image signal. In FIG. 3, thephotoelectric conversion layer 51 and one of the storage capacitors 53are shown as a pixel 50, and the pixel 50 is connected to one of theTFTs 52. Details of the other pixels 50 are omitted from illustration.Since amorphous selenium tends to change its structure and lose itsfunction at high temperatures, it needs to be used within a certaintemperature range. Therefore, some means for cooling the radiationdetector 40 should preferably be provided in the electronic cassette 24.

The TFTs 52 connected to the respective pixels 50 are connected torespective gate lines 54 extending parallel to the rows and respectivesignal lines 56 extending parallel to the columns. The gate lines 54 areconnected to a line scanning driver 58, and the signal lines 56 areconnected to a multiplexer 66 serving as a reading circuit.

The gate lines 54 are supplied with control signals Von, Voff forturning on and off the TFTs 52 along the rows from the line scanningdriver 58. The line scanning driver 58 comprises a plurality of switchesSW1 for switching between the gate lines 54 and an address decoder 60for outputting a selection signal for selecting one of the switches SW1at a time. The address decoder 60 is supplied with an address signalfrom the cassette controller 46.

The signal lines 56 are supplied with electric charges stored in thestorage capacitors 53 of the pixels 50 through the TFTs 52 arranged inthe columns. The electric charges supplied to the signal lines 56 areamplified by amplifiers 62 connected respectively to the signal lines56. The amplifiers 62 are connected through respective sample and holdcircuits 64 to the multiplexer 66. The multiplexer 66 comprises aplurality of switches SW2 for successively switching between the signallines 56 and an address decoder 68 for outputting a selection signal forselecting one of the switches SW2 at a time. The address decoder 68 issupplied with an address signal from the cassette controller 46. Themultiplexer 66 has an output terminal connected to an A/D converter 70.A radiographic image signal generated by the multiplexer 66 based on theelectric charges from the sample and hold circuits 64 is converted bythe A/D converter 70 into a digital image signal representingradiographic image information, which is supplied to the cassettecontroller 46.

The TFTs 52 which function as switching devices may be combined withanother image capturing device such as a CMOS (Complementary Metal-OxideSemiconductor) image sensor or the like. Alternatively, the TFTs 52 maybe replaced with a CCD (Charge-Coupled Device) image sensor for shiftingand transferring electric charges with shift pulses which correspond togate signals in the TFTs.

FIG. 4 shows in block form the image capturing system 10 which comprisesthe image capturing apparatus 22, the electronic cassette 24, the powerfeeder 25, the display device 26, and the console 28.

The console 28 is connected to a radiology information system (RIS,information management system) 29 which stores and generally managesradiographic image information handled by the radiological department ofthe hospital and other information, e.g., ordering informationrepresentative of the number of times that the patient 14 is to beimaged (the number of radiographic images thereof to be captured, thenumber of times that the patient 14 is to be exposed to the radiationX). Also, the RIS 29 is connected to a hospital information system (HIS)33 which generally manages medical information in the hospital.Alternatively, the console 28 may be connected to a consolidated systemwhich combines the functions of the HIS 33 and the RIS 29.

The image capturing apparatus 22 comprises an image capturing switch 72,a radiation source 74, a transceiver 76, and a radiation sourcecontroller 78. The transceiver 76 receives image capturing conditionsfrom the console 28 by way of wireless communications and transmits animage capturing completion signal, etc. to the console 28 by way ofwireless communications. The radiation source controller 78 controls theradiation source 74 based on an image capturing start signal suppliedfrom the image capturing switch 72 and image capturing conditionssupplied from the console 28. The radiation source 74 outputs theradiation X under the control of the radiation source controller 78.

The power feeder 25 comprises a power supply 80 connected to an externalpower supply or the like, not shown, a transceiver 82 for receiving apower feeding start signal, etc. from the console 28 by way of wirelesscommunications and sending ID information (ID data), etc. of the powerfeeder 25 to the console 28 by way of wireless communications, an LCresonator (feeding unit) 84 for converting electric energy from thepower supply 80 into the magnetic field M and applying the magneticfield M, or in other words, contactlessly (wirelessly) supplyingelectric energy, to the electronic cassette 24, and a power feedingcontroller 86 for energizing the LC resonator 84 based on the powerfeeding start signal supplied from the console 28.

FIG. 5 shows in block form the image capturing system 10, showingstructural details of the electronic cassette 24 as the radiationdetecting apparatus according to the present embodiment.

As shown in FIGS. 4 and 5, the electronic cassette 24 includes theradiation detector 40, the battery 44, the wireless power receiver 49,the cassette controller 46, and the transceiver 48.

The battery 44 comprises a chargeable secondary battery such as alithium ion battery or the like, and serves as a power supply forsupplying electric power to various parts of the electronic cassette 24,which include the radiation detector 40, the cassette controller 46, andthe transceiver 48. The battery 44 may alternatively comprise anelectric storage device such as an electric double layer capacitor orany of other devices insofar as it can be charged and serve as a powersupply for the electronic cassette 24.

The wireless power receiver 49 has a function to receive the electricpower contactlessly (wirelessly) supplied from the power feeder 25 andsupply the received electric power to the battery 44, i.e., charge thebattery 44 with the received electric power. The wireless power receiver49 has an LC resonator 88 for receiving the magnetic field M appliedfrom the LC resonator 84 of the power feeder 25 into electric energy(high-frequency power), and a charging circuit 90 for converting theelectric energy from the LC resonator 88 into desired electric power andsupplying the electric power to the battery 44. Specifically, the LCresonator 88 comprises an LC resonant circuit having a coil and acapacitor, and the charging circuit 90 rectifies the electric currentgenerated by the LC resonator 88 into a constant electric current, andcharges the battery 44 with the constant electric current.

The wireless power receiver 49 also has a detecting LC resonator 94disposed parallel to the LC resonator 88 and smaller in size than the LCresonator 88, and an energy detector 96 for detecting electric energyconverted from the magnetic field M by the detecting LC resonator 94.The detecting LC resonator 94 also comprises an LC resonant circuithaving a coil and a capacitor, as with the LC resonator 88. When theenergy detector 96 detects the electric energy converted from themagnetic field M by the detecting LC resonator 94, the energy detector96 detects that the electronic cassette 24 is positioned within afeeding area of the power feeder 25, and sends a feeding area detectionsignal to the cassette controller 46.

Each of the LC resonators 84, 88, 94 has an LC resonance circuitcomprising a coil and a capacitor. The power feeder 25 can contactlessly(wirelessly) supply electric power to the electronic cassette 24according to the known power transmission technology which utilizes theresonance of the magnetic field M (magnetic resonance) from the LCresonator 84 to the LC resonator 88.

As shown in FIG. 5, the cassette controller 46 comprises an addresssignal generator 98, an image memory 100, an operation manager 102, acassette ID memory 104, and a data manager 106. The address signalgenerator 98 supplies address signals to the address decoder 60 of theline scanning driver 58 of the radiation detector 40 and the addressdecoder 68 of the multiplexer 66 of the radiation detector 40. The imagememory 100 stores radiographic image information detected by theradiation detector 40. Specifically, the image memory 100 storesradiographic image information generated by the radiation detector 40when the radiation X is applied to the radiation detector 40 andconverted into electric charges, and the electric charges are stored andthen read and converted into digital signals.

The operation manager 102 controls operation of the wireless powerreceiver 49 and the battery 44, and also controls overall operation ofthe electronic cassette 24. The operation manager 102 comprises anend-of-A/D-conversion determining unit 107, a charging controller 108,and an image capturing controller 109.

The end-of-A/D-conversion determining unit 107 determines whether theA/D conversion of radiographic image information by the A/D converter 70is ended or not. The charging controller 108 generates a signal (feedinginhibition signal or charging inhibition signal) for inhibiting thepower feeder 25 from feeding the electronic cassette 24, i.e., forinhibiting the electronic cassette 24 from being charged by the powerfeeder 25, before the image capturing apparatus 22 starts capturing aradiographic image, and generates a signal (feeding permission signal orcharging permission signal) for permitting the power feeder 25 to feedthe electronic cassette 24, i.e., for permitting the electronic cassette24 to be charged by the power feeder 25, when the end-of-A/D-conversiondetermining unit 107 judges that the A/D conversion of radiographicimage information by the A/D converter 70 is ended. The chargingcontroller 108 may be configured as a plurality of controllers (signalgenerators) for generating the respective signals. The image capturingcontroller 109 generates control signals (image capturing permissionsignal and image capturing inhibition signal) for permitting the imagecapturing apparatus 22 to capture a radiographic image and inhibitingthe image capturing apparatus 22 from capturing a radiographic image.

The feeding inhibition signal and the feeding permission signal whichare generated by the charging controller 108 and the image capturingpermission signal and the image capturing inhibition signal which aregenerated by the image capturing controller 109 are transmitted from thetransceiver 48 to the console 28. When the console 28 receives thesesignals, the console 28 performs a control process for inhibiting(stopping) the contactless power feeding (wireless power feeding) fromthe power feeder 25 and a control process for starting (resuming) thecontactless power feeding (wireless power feeding) from the power feeder25, and also performs a control process for permitting (starting) theimage capturing by the image capturing apparatus 22 and a controlprocess for inhibiting (stopping) the image capturing by the imagecapturing apparatus 22. Alternatively, the electronic cassette 24 maydirectly transmit the feeding inhibition (permission) signal and theimage capturing permission (inhibition) signal to the power feeder 25,not through the console 28, and the power feeding controller 86 and theradiation source controller 78 may perform the control process forinhibiting (starting) the contactless power feeding (wireless powerfeeding) and the control process for starting (inhibiting) the imagecapturing.

The cassette ID memory 104 stores cassette ID information foridentifying the electronic cassette 24. The data manager 106 manages IDinformation (ID data) for identifying the power feeder 25 which feedsthe electronic cassette 24 and a feeding area detection signal from theenergy detector 96.

The transceiver 48 receives a transmission request signal from theconsole 28 and the ID information of the power feeder 25 by way ofwireless communications, and transmits the radiographic imageinformation, the cassette ID information, a wireless feeding enablesignal, the feeding inhibition signal, the feeding permission signal,the image capturing permission signal, the image capturing inhibitionsignal, etc. to the console 28.

As shown in FIG. 4, the display device 26 comprises a receiver 110 forreceiving the radiographic image information from the console 28, adisplay controller 112 for processing the received radiographic imageinformation, and a display unit 114 for displaying the radiographicimage information processed by the display controller 112.

The console 28 comprises a transceiver 116, an image capturing conditionmanager 118, an image processor 120, an image memory 122, a patientinformation manager 124, a cassette information manager 126, and a powerfeeding information manager 128. The console 28 may be located outsideof the operating room 12 insofar as it can reliably transmit and receivesignals to and from the image capturing apparatus 22, the electroniccassette 24, the power feeder 25, and the display device 26.

The transceiver 116 of the console 28 transmits and receives necessaryinformation including radiographic image information, the feedinginhibition (permission) signal, and the image capturing permission(inhibition) signal to and from the image capturing apparatus 22, theelectronic cassette 24, the power feeder 25, and the display device 26by way of wireless communications. The image capturing condition manager118 manages image capturing conditions required for the image capturingapparatus 22 to capture radiographic images, and also performs thecontrol process for starting the image capturing by the image capturingapparatus 22 and the control process for inhibiting the image capturingby the image capturing apparatus 22 based on the image capturingpermission signal and the image capturing inhibition signal from theimage capturing controller 109. The image processor 120 processesradiographic image information transmitted from the electronic cassette24. The image memory 122 stores the radiographic image informationprocessed by the image processor 120. The patient information manager124 manages patient information of the patient 14 whose images are to becaptured. The cassette information manager 126 manages the wirelessfeeding enable signal and the cassette information including thecassette ID information transmitted from the electronic cassette 24. Thepower feeding information manager 128 manages the operation control ofthe power feeder 25 and ID information sent from the power feeder 25,and also performs the control process for inhibiting the power feedingby the power feeder 25 and the control process for starting (resuming)the power feeding by the power feeder 25 based on the feeding inhibitionsignal and the feeding permission signal from the charging controller108.

The image capturing conditions refer to conditions for determining atube voltage, a tube current, an irradiation time, etc. required toapply radiation X at an appropriate dose to an area to be imaged of thepatient 14. The image capturing conditions may include an area to beimaged of the patient 14, an image capturing method, etc., for example.The image capturing conditions may also include conditions representingthe number of times that a radiographic image is to be captured, asordering information from the RIS 29, for example. The patientinformation refers to information for identifying the patient 14, suchas the name, gender, patient ID number, etc. of the patient 14. Orderinginformation for instructing the image capturing system 10 to capture aradiation image, including the image capturing conditions and thepatient information, can be set directly on the console 28 or can besupplied from an external source to the console 28 via the RIS 29. Thecassette information includes the wireless feeding enable signal fromthe data manager 106 in addition to the cassette ID information foridentifying the electronic cassette 24.

The image capturing system 10 according to the first embodiment isbasically constructed as described above, and operation of the imagecapturing system 10 will be described below with reference to aflowchart shown in FIG. 6.

The image capturing system 10 is installed in the operating room 12 andused when radiographic images of the patient 14 are required by thesurgeon 18 who is performing a surgical operation on the patient 14.Before radiographic images of the patient 14 are captured, patientinformation of the patient 14 to be imaged and the number ofradiographic images to be captured are registered in the patientinformation manager 124 of the console 28. If an area to be imaged ofthe patient 14 and an image capturing method have already been known,they are registered beforehand as image capturing conditions in theimage capturing condition manager 118. These information and conditionscan be registered by being acquired from the RIS 29. After the abovepreparatory process is finished, the surgeon 18 performs a surgicaloperation on the patient 14.

In step S1 shown in FIG. 6, for capturing radiographic images of thepatient 14 during the surgical operation, the surgeon 18 or aradiological technician working on the image capturing system 10 placesthe electronic cassette 24 in a desired position between the patient 14and the surgical table 16 with the irradiated surface 36 facing theimage capturing apparatus 22.

At the same time that the console 28 starts to operate or when thesurgeon 18 or the radiological technician turns on an operation startswitch, not shown, the power feeder 25 is energized under givenoperating conditions (a low output operation mode). The electroniccassette 24 is now detected as being placed within the feeding area ofthe power feeder 25 by the detecting LC resonator 94 and the energydetector 96 of the wireless power receiver 49. Specifically, the energydetector 96 functions as a power feeding enable/disable detector fordetecting whether the electronic cassette 24 is placed within thefeeding area of the power feeder 25 or not. At this time, the powerfeeding controller 86 of the power feeder 25 operates in the low outputoperation mode for applying, from the LC resonator 84, a relatively weakmagnetic field M which can be detected by the detecting LC resonator 94and the energy detector 96 of the wireless power receiver 49. Therefore,the power consumption of the power feeder 25 is kept at a low level.

In the electronic cassette 24, the energy detector 96 supplies a feedingarea detection signal to the data manager 106. In response to thefeeding area detection signal, the data manager 106 receives the IDinformation of the power feeder 25 which is stored in the power feedinginformation manager 128 from the console 28, and transmits the wirelessfeeding enable signal to the cassette information manager 126 of theconsole 28.

The energy detector 96 also supplies the feeding area detection signalto the operation manager 102. In response to the feeding area detectionsignal, the operation manager 102 turns on the electronic cassette 24 tomake it ready for use, thereby completing preparations for imagecapturing. Of course, the electronic cassette 24 may have, for example,on a side thereof, a power supply switch, not shown, which can beoperated by the surgeon 18 or the radiological technician.

After the preparations for image capturing have been completed, thecassette controller 46 or the cassette information manager 126 of theconsole 28 manages the remaining power level of the battery 44 todetermine whether the remaining power level is sufficient or not, i.e.,whether the battery 44 needs to be charged or not, in step S2. If it isjudged that the battery 44 needs to be charged (“NO” in step S2), thenthe cassette information manager 126 sends a power feeding start signalto the power feeding controller 86 of the power feeder 25. The powerfeeder 25 now supplies electric power to the electronic cassette 24,i.e., charges the battery 44 of the electronic cassette 24 with adesired amount of electric power at a desired timing in step S3. If theremaining power level of the battery 44 runs low during the surgicaloperation, then the battery 44 may be charged while it is being kept inthe given image capturing position. If the remaining power level of thebattery 44 runs low during the preparations for image capturing, i.e.,while the electronic cassette 24 is being placed in position, or beforeradiographic images start being captured, then the battery 44 can becharged in a contactless (wireless) fashion immediately before or afterthe surgical operation is started, so that the preparations for imagecapturing can be completed quickly.

For contactlessly (wirelessly) supplying electric power to theelectronic cassette 24, the power feeder 25 may be energized to applythe magnetic field M from the LC resonator 84 to the electronic cassette24 under given operating conditions for a stronger level than in the lowoutput operation mode (high output operation mode, power feedingoperation mode). In the electronic cassette 24, the energy received bythe detecting LC resonator 94 as well as the energy received by the LCresonator 88, may be used to charge the battery 44 through the chargingcircuit 90, for thereby quickly charging the battery 44.

The image capturing system 10 allows the console 28 to confirm the IDinformation of the power feeder 25 that is associated with theelectronic cassette 24. Accordingly, even if the image capturing system10 includes a plurality of power feeders that are selectively usable,the electronic cassette 24 can be appropriately and selectively suppliedwith electric power from a desired selected one of the power feedersbased on the ID information confirmed by the console 28. As a result,wasteful power consumption and erroneous operation can be avoided.

If it is judged that the remaining power level of the battery 44 issufficient (“YES” in step S2), then the charging controller 108transmits a feeding inhibition signal (step S4), and the image capturingcontroller 109 transmits an image capturing permission signal (step S5).Therefore, the power feeder 25 is brought into a feeding inhibitionstate and the image capturing apparatus 22 is brought into an imagecapturing start standby state capable of capturing radiographic imagesunder the control of the console 28 (the image capturing conditionmanager 118 and the power feeding information manager 128).Consequently, while a radiographic image is being captured, theelectronic cassette 24 is prevented from being contactlessly(wirelessly) supplied with electric power. Therefore, the voltagesupplied from the battery 44 to the radiation detector 40 is preventedfrom becoming unstable and fluctuating greatly, and noise caused by themagnetic field M applied from the power feeder 25 is prevented fromadversely affecting the radiation detector 40, so that a capturedradiographic image is effectively prevented from suffering from noiseand decreasing in quality.

In step S6, the surgeon 18 or the radiological technician moves theimage capturing apparatus 22 to a position facing the electroniccassette 24, and then turns on the image capturing switch 72 to capturea radiographic image of the patient 14. The image capturing switch 72comprises a two-stage switch including first and second stages, forexample. The first stage starts up the radiation source 74 at a giventube current, and then the second stage operates the radiation source 74to emit the radiation X.

When the surgeon 18 or the radiological technician operates the imagecapturing switch 72, the radiation source controller 78 of the imagecapturing apparatus 22 sends a request to the console 28 for sending theimage capturing conditions. Based on the received request, the console28 sends the image capturing conditions for an area to be imaged of thepatient 14 which are registered in the image capturing condition manager118 and the number of radiographic images to be captured, to the imagecapturing apparatus 22. When the radiation source controller 78 receivesthe image capturing conditions, it controls the radiation source 74 toapply radiation X at a given dose to the patient 14 according to theimage capturing conditions. The image capturing conditions may be sentin advance from the console 28 to a memory, not shown, in the radiationsource controller 78.

The radiation X which has passed through the patient 14 is applied tothe grid 38, which removes scattered rays of the radiation X. Then, theradiation X is applied to the radiation detector 40, and converted intoelectric signals by the photoelectric conversion layer 51 of the pixels50 of the radiation detector 40. The electric signals are stored aselectric charges in the storage capacitors 53 (see FIG. 3). The storedelectric charges (signal charges), which represent radiographic imageinformation of the patient 14, are read from the storage capacitors 53according to address signals which are supplied from the address signalgenerator 98 of the cassette controller 46 to the line scanning driver58 and the multiplexer 66.

Specifically, in response to the address signal supplied from theaddress signal generator 98, the address decoder 60 of the line scanningdriver 58 outputs a selection signal to select one of the switches SW1,which supplies the control signal Von to the gates of the TFTs 52connected to the gate line 54 corresponding to the selected switch SW1.In response to the address signal supplied from the address signalgenerator 98, the address decoder 68 of the multiplexer 66 outputs aselection signal that successively turns the switches SW2 on in order toswitch between the signal lines 56, for thereby reading the electriccharges stored in the storage capacitors 53 of the pixels 50 connectedto the selected gate line 54, through the signal lines 56.

The electric charges read from the storage capacitors 53 of the pixels50 connected to the selected gate line 54 are amplified by therespective amplifiers 62, sampled by the sample and hold circuits 64,and supplied to the multiplexer 66. Based on the supplied electriccharges, the multiplexer 66 generates and supplies a radiographic imagesignal to the A/D converter 70, which converts the radiographic imagesignal into a digital signal (step S7). The digital signal whichrepresents the radiographic image information is stored in the imagememory 100 of the cassette controller 46.

Similarly, the address decoder 60 of the line scanning driver 58successively turns on the switches SW1 to switch between the gate lines54 according to the address signal supplied from the address signalgenerator 98. The electric charges stored in the storage capacitors 53of the pixels 50 connected to the successively selected gate lines 54are read through the signal lines 56, and processed by the multiplexer66 and the A/D converter 70 into digital signals (step S7), which arestored in the image memory 100 of the cassette controller 46.

The radiographic image information represented by the digital signalsstored in the image memory 100 is transmitted to the console 28 by wayof wireless communications. The radiographic image informationtransmitted to the console 28 is received by the transceiver 116,processed by the image processor 120, and then stored in the imagememory 122 in association with the patient information of the patient 14registered in the patient information manager 124.

The radiographic image information processed by the image processor 120is transmitted from the console 28 to the display device 26. In thedisplay device 26, the receiver 110 receives the radiographic imageinformation, and the display controller 112 controls the display unit114 to display a radiographic image based on the radiation imageinformation. The surgeon 18 can perform the surgical operation on thepatient 14 while visually confirming the radiographic image displayed onthe display unit 114.

Even if the remaining power level of the battery 44 of the electroniccassette 24 runs low due to a plurality of radiographic images capturedduring the surgical operation, since the electronic cassette 24 iscontactlessly (wirelessly) supplied with electric power from the powerfeeder 25, the battery 44 of the electronic cassette 24 can be chargedwith the electronic cassette 24 being kept in the image capturingposition. While radiographic images are being captured, particularlyuntil the A/D conversion of the electric charges is finished, since theradiographic image information is represented by an analog signal, ittends to be greatly affected by noise caused by the contactless(wireless) power feeding, and the captured radiographic image is liableto contain the noise. Consequently, the image capturing system 10 ishighly likely to fail to acquire radiographic images of high quality.

The image capturing system 10 according to the present embodiment isarranged to overcome the above difficulties as follows: The imagecapturing system 10 includes the end-of-A/D-conversion determining unit107, the charging controller 108, and the image capturing controller109, which operate to inhibit the contactless (wireless) power feedingat least until the conversion of the analog radiographic imageinformation detected by the radiation detector 40 into digital signalsis completed.

Specifically, when the image capturing system 10 starts to prepareitself for capturing radiographic images, e.g., when the surgeon 18 orthe radiological technician turns on the image capturing switch 72 orthe radiation source controller 78 of the image capturing apparatus 22sends a request to the console 28 for sending the image capturingconditions, the console 28 sends an image capturing start signal to theelectronic cassette 24 to operate the cassette controller 46, therebycompleting preparations for capturing radiographic images in theelectronic cassette 24, at the same time that or before the console 28controls the image capturing apparatus 22 (steps S1, S2). At the sametime, in the electronic cassette 24, the charging controller 108generates a feeding inhibition signal to inhibit the power feeder 25from supplying electric power to the electronic cassette 24, and theimage capturing controller 109 generates an image capturing permissionsignal to make the image capturing apparatus 22 ready for capturingradiographic images (steps S4, S5).

When the image capturing system 10 starts to capture a radiographicimage (step S6), the radiographic image information detected by theradiation detector 40 is converted from analog signals into digitalsignals by the A/D converter 70 (step S7). The application of theradiation X and the A/D conversion of the detected radiographic imageinformation are performed until a preset number of radiographic imagesare captured, i.e., until the radiation X is applied to the subject 14by a preset number of times (step S8).

When the preset number of radiographic images have been captured (“YES”in step S8), the end-of-A/D-conversion determining unit 107 determineswhether the A/D conversion immediately after the number of radiographicimages have been captured is finished or not (step S9). If theend-of-A/D-conversion determining unit 107 judges that the A/Dconversion is finished, i.e., if the end-of-A/D-conversion determiningunit 107 judges that all the radiographic image information produced inthe present image capturing process has been converted into digitalsignals (“YES” in step S9), then the charging controller 108 generates afeeding permission signal in step S10.

The feeding permission signal is transmitted from the electroniccassette 24 to the console 28. The power feeding information manager 128manages the operation control of the power feeder 25 to perform thecontrol process for starting the power feeding by the power feeder 25,or the control process for bringing the power feeder 25 into a powerfeeding start standby state (power feeding resumption standby state) toallow the power feeder 25 to start the power feeding immediately (stepS12). When the A/D conversion of all the acquired radiographic imageinformation is finished after the preset number of radiographic imageshave been captured, therefore, electric power can quickly be suppliedcontactlessly (wirelessly) to the battery 44 (step S13). If the controlprocess for bringing the power feeder 25 into the power feeding startstandby state is carried out, then after the console 28 has received thefeeding permission signal, the cassette controller 46 or the cassetteinformation manager 126 checks the remaining power level of the battery44 (step S11), and then the control process for starting the powerfeeding is performed. The feeding permission signal may be directly sentfrom the electronic cassette 24 to the power feeder 25, not through theconsole 28, and the power feeding controller 86 and the cassettecontroller 46 may perform the control process for starting the powerfeeding and the control process for bringing the power feeder 25 intothe power feeding start standby state.

The end-of-A/D-conversion determining unit 107 may preferably determinewhether the A/D conversion is finished or not (step S9) based on whethera period (storage period) in which the radiation X that has passedthrough the patient 14 is applied to the radiation detector 40 andconverted into electric signals by the photoelectric conversion layer 51of the pixels 50, and the electric signals are stored as signal chargesin the storage capacitors 53, a period (readout period) in which theelectric charges stored in the storage capacitors 53 are read, and aperiod (A/D conversion period) in which the read electric charges(analog signal) are converted into digital signals by the A/D converter70 have elapsed or not. In these three periods, added noise tends toadversely affect the image signal (radiographic image information)significantly. Specifically, in the storage period and the readoutperiod, added noise tends to adversely affect the electric chargessignificantly because the electric charges are low in level. In the A/Dconversion period, the analog signal is less resistant to noise than thedigital signal, and noise added to the analog signal is likely to beconverted into a digital signal and appear in the image data.

The storage period includes a time in which the radiation source 74applies the radiation X. After the storage capacitors 53 have started tostore electric charges, the radiation source 74 should start applyingthe radiation X as quickly as possible. Then, the electric chargesstored in the storage capacitors 53 should start being read outimmediately after the radiation source 74 has stopped applying theradiation X. If any time lags of these operations are minimized, then aso-called dark current is reduced so as to further improve the qualityof the acquired radiographic image. The readout period referred to aboveis a period in which the TFTs 52 are turned on to send signals throughthe amplifiers 62 to the A/D converter 70. The readout period and theA/D conversion period are essentially synchronous with each other.Practically, however, the readout period starts slightly earlier thanthe A/D conversion period.

The end-of-A/D-conversion determining unit 107 should preferablydetermine whether the A/D conversion is finished or not (step S9) basedon whether the storage of the digital signals representative of theradiographic image information in the image memory 100 is finished afterthe A/D conversion period. In this case, during data transfer to theimage memory 100, during which data may be susceptible to noise thoughnot as significantly as during the A/D conversion, the data areeffectively prevented from being adversely affected by noise which maybe caused by the contactless (wireless) electric power transmission fromthe power feeder 25 to the electronic cassette 24, and hence from beingcorrupted. Alternatively, the time at which the transmission of theimage data from the image memory 100 via the transceivers 48, 116 iscompleted may be judged as the time at which the A/D conversion isfinished, so that the image data will be more effectively prevented frombeing adversely affected by noise which may be caused by the contactless(wireless) electric power transmission.

The feeding permission signal may be generated in step S10 at anydesired timing after the A/D conversion (step S9), e.g., after thetransmission of the digital signals from the electronic cassette 24 tothe console 28 is completed.

As described above, even though the feeding inhibition signal isgenerated (step S4) to inhibit the power feeding during the capture of aradiographic image, the image capturing system 10 can quickly start(resume) supplying electric power to the battery 44 after the A/Dconversion has been finished (steps S10 through S13), i.e., at a timewhen the radiographic image information is relatively less susceptibleto noise. This is particularly effective when the battery 44 needs to bequickly charged for the next image capturing process after the remainingpower level thereof has been greatly reduced in the previous imagecapturing process. If another image capturing process is to be performedafter the sequence of steps S1 through S13, then control may return fromstep S13 or S11 to step S1.

The image capturing system 10 may be configured to charge the battery 44under the control of the console 28 at desired times other than whenradiographic images are captured.

As described above, with the image capturing system 10 according to thepresent embodiment, even though the electronic cassette 24 is placed ina desired image capturing position with respect to the patient 14, thepower feeder 25 can easily supply electronic power to the electroniccassette 24. Even if the battery 44 of the electronic cassette 24 needsto be charged during the surgical operation, the battery 44 can becharged without the need for moving the electronic cassette 24.Accordingly, the electronic cassette 24 and the image capturing system10 can be handled with ease as a whole. Furthermore, the process ofcapturing a radiographic image and the surgical operation areeffectively prevented from being interrupted and prolonged due to a lowremaining power level of the battery 44 of the electronic cassette 24.

The image capturing system 10 (the electronic cassette 24) has theend-of-A/D-conversion determining unit 107, the charging controller 108,and the image capturing controller 109, and a feeding inhibition signalis generated before the image capturing system 10 starts to capture aradiographic image, and a feeding permission signal is generated afterthe A/D conversion of radiographic image information is ended. As thecontactless (wireless) power feeding is inhibited at least until theconversion of the analog radiographic image information detected by theradiation detector 40 into digital signals is completed, the analogradiographic image information that is susceptible to noise is preventedfrom being adversely affected by noise caused by the contactless(wireless) power feeding from the power feeder 25. Therefore, it ispossible to acquire radiographic images of high quality. Since the imagecapturing controller 109 generates an image capturing permission signalwhen the charging controller 108 generates a feeding inhibition signal,the contactless (wireless) power feeding from the power feeder 25 ismore reliably inhibited during the image capturing process.

After the A/D conversion, i.e., at a time when radiographic imageinformation is relatively less susceptible to noise, the power feeder 25quickly starts (resumes) the power feeding in response to a feedingpermission signal from the charging controller 108. Therefore, even ifthe remaining power level of the battery 44 is greatly lowered by animage capturing process, the battery 44 can quickly be charged after theimage capturing process and made ready for a next image capturingprocess.

When the electronic cassette 24 is placed within the feeding area of thepower feeder 25, the electronic cassette 24 and the power feeder 25automatically exchanges information with each other through the console28, and the electronic cassette 24 is automatically brought into a statecapable of capturing a radiographic image. Consequently, the electroniccassette 24 is not required to have a manual power supply switch, andthe surgeon 18 or the radiological technician is prevented from making amistake not to capture a radiographic image by forgetting to operatingsuch a manual power supply switch. Accordingly, the electronic cassette24 and the image capturing system 10 can be handled with greater ease asa whole. If the energy detector 96 of the electronic cassette 24 doesnot detect the desired magnetic field M, then the data manager 106 maysend a wireless feeding disable signal, for example, to the cassetteinformation manager 126, from which the wireless feeding disable signalis sent to the display device 26 for indicating to the surgeon 18 or theradiological technician that it is not possible to supply electric powerfrom the power feeder 25 to the electronic cassette 24, on the displayunit 114.

FIG. 7 is a block diagram of a radiographic image capturing system 10 aaccording to a second embodiment of the present invention.

As shown in FIG. 7, the radiographic image capturing system 10 aaccording to the second embodiment is basically the same as theradiographic image capturing system 10 (see FIGS. 4 and 5) according tothe first embodiment except that the RIS 29 and the HIS 33 are notconnected to the console 28. However, the radiographic image capturingsystem 10 a according to the second embodiment is different from theradiographic image capturing system 10 according to the first embodimentas to an image capturing process, particularly a control process forcontactless (wireless) power feeding. Specifically, the radiographicimage capturing system 10 a performs first through third image capturingsequences shown in FIGS. 8 through 10. The radiographic image capturingsystem 10 a is preferably used as a radiographic image capturing systemthat is not connected to the RIS 29 and the HIS 33, e.g., a radiographicimage capturing system in a hospital which is free of the RIS 29 and theHIS 33 or a radiographic image capturing system to accompany a doctorwhen going the rounds in a hospital.

The first image capturing sequence of the radiographic image capturingsystem 10 a will first be described below with reference to FIG. 8.Those control steps shown in FIG. 8 which are denoted by the same stepnumbers as those shown in FIG. 6 represent the same or identicaloperations, and will not be described in detail below. The same holdstrue for the control steps shown in FIGS. 9 and 10.

The first image capturing sequence is basically the same as the imagecapturing sequence of the image capturing system 10 shown in FIG. 6except that step S8 a is carried out instead of step S8 shown in FIG. 6.

Since the RIS 29 is not connected to the image capturing system 10 a,the image capturing system 10 a is unable to acquire orderinginformation about the number of times that the patient 14 is to beimaged (the number of radiographic images thereof to be captured, thenumber of times that the patient 14 is to be exposed to the radiationX). In step S8 a, it is determined whether the application of theradiation X by the image capturing apparatus 22 is finished or not,e.g., whether the image capturing switch 72 is turned off or not.

If it is judged that the application of the radiation X is finished(“YES” in step S8 a), then information indicating that the imagecapturing switch 72 is turned off is supplied to the charging controller108 under the control of the console 28. In step S9, theend-of-A/D-conversion determining unit 107 determines whether the A/Dconversion of all the radiographic image information obtained in thepresent image capturing process is finished or not.

According to the first image capturing sequence of the image capturingsystem 10 a, if it is judged that the application of the radiation X isfinished (“YES” in step S8 a) and the A/D conversion is finished (“YES”in step S9), then the charging controller 108 generates a feedingpermission signal in step S10. Therefore, even though the number oftimes that the patient 14 is to be imaged is not acquired from the RIS29, the end of the capturing of the desired number of radiographicimages can be judged from the stop of the application of the radiationX, e.g., the turning-off of the image capturing switch 72. Accordingly,noise caused by the contactless (wireless) power feeding from the powerfeeder 25 is prevented from adversely affecting the analog radiographicimage information, and the image capturing system 10 a can quickly start(resume) supplying electric power to the battery 44 after the A/Dconversion, in response to the feeding permission signal from thecharging controller 108.

A second image capturing sequence of the image capturing system 10 awill be described below with reference to FIG. 9. The second imagecapturing sequence includes steps S8 b, S9 b instead of steps S8 a, S9of the first image capturing sequence shown in FIG. 8.

In step S8 b shown in FIG. 9, the end-of-A/D-conversion determining unit107 determines whether the A/D conversion of radiographic imageinformation by the A/D converter 70 is ended or not, as with steps S9shown in FIGS. 6 and 8. Then, if it is judged that the A/D conversion isfinished (“YES” in step S8 b), then control goes to step S9 b.

In step S9 b, the charging controller 108 determines whether a giventime (constant time) has elapsed after the end of the A/D conversion ornot. If it is judged that the given time has elapsed after the end ofthe A/D conversion (“YES” in step S9 b), then the charging controller108 generates a feeding permission signal in step S10. Since the elapseof the given time after the end of the A/D conversion is determined instep S9 b, a data transfer time (saving time) is secured fortransferring the digital radiographic image information to the imagememory 100. In other words, the charging controller 108 generates afeeding permission signal after the data transfer time has elapsed.Consequently, noise due to the power feeding is effectively preventedfrom adversely affecting the image data being transferred to the imagememory 100.

A third image capturing sequence of the image capturing system 10 a willbe described below with reference to FIG. 10. The third image capturingsequence includes step S7 c instead of steps S7, S8 a, S9 of the firstimage capturing sequence shown in FIG. 8.

In step S7 c shown in FIG. 10, it is determined whether a given time(constant time) has elapsed after the image capturing apparatus 22 hasstarted to capture a radiographic image, i.e., after the radiation X hasstarted being applied, or not. The given time may start being measuredfrom a time at which the image capturing switch 72 (the second stagereferred to above) is operated or a time at which the radiation detector40 starts detecting the radiation X, for example.

If it is judged that the given time has elapsed after the imagecapturing apparatus 22 has started to capture a radiographic image(“YES” in step S7 c), then the charging controller 108 generates afeeding permission signal in step S10. Consequently, the contactless(wireless) power feeding is prevented from being performed during thestorage period, the readout period, the A/D conversion period, asreferred to above, and also during the data transfer time (saving time)for transferring the digital radiographic image information to the imagememory 100. Therefore, noise due to the contactless (wireless) powerfeeding is effectively prevented from adversely affecting the image databeing transferred to the image memory 100. In this case, theend-of-A/D-conversion determining unit 107 may judge that the A/Dconversion is finished in view of the given time from the start of theapplication of the radiation X. Thus, the function of theend-of-A/D-conversion determining unit 107 may be integrated into thecharging controller 108.

With the image capturing system 10 a, as with the image capturing system10, it is possible to generate the feeding permission signal (step S10)after the radiographic image information has been transmitted from theimage memory 100 via the transceivers 48, 116 to the console 28.

If the number of radiographic images to be captured can be set by theconsole 28, then the image capturing system 10 a may be configured tocarry out a control sequence which is the same as the control sequenceshown in FIG. 6 in accordance with the set number of radiographic imagesto be captured.

FIG. 11 is a block diagram of a radiographic image capturing system 10 baccording to a first modification of the radiographic image capturingsystem 10 shown in FIG. 4.

In the radiographic image capturing systems 10, 10 a described above,the end-of-A/D-conversion determining unit 107, the charging controller108, and the image capturing controller 109 for controlling theinhibition of the power feeding by the power feeder 25 and alsocontrolling the start of the image capturing by the image capturingapparatus 22 are incorporated in the electronic cassette 24. In theradiographic image capturing system 10 b, an end-of-A/D-conversiondetermining unit 107 a, a charging controller 108 a, and an imagecapturing controller 109 a are incorporated in the console 28.

In the radiographic image capturing system 10 b, theend-of-A/D-conversion determining unit 107 a judges that the A/Dconversion is finished when the digital radiographic image informationhas been transmitted from the image memory 100 to the console 28, andsends information about the above judgment to the charging controller108 a and the image capturing controller 109 a, for thereby performingan operation sequence based on the image capturing sequence shown inFIG. 6. The end-of-A/D-conversion determining unit 107, the chargingcontroller 108, and the image capturing controller 109 that areincorporated in the electronic cassette 24 may be disabled under thecontrol of the console 28. Alternatively, the radiographic imagecapturing system 10 b may employ a simplified electronic cassette whichis free of the end-of-A/D-conversion determining unit 107, the chargingcontroller 108, and the image capturing controller 109.

As shown in FIG. 11, an end-of-A/D-conversion determining unit 107 b, acharging controller 108 b, and an image capturing controller 109 b maybe provided in the image capturing apparatus 22, in addition to orinstead of the end-of-A/D-conversion determining unit 107 a, thecharging controller 108 a, and the image capturing controller 109 a, andan end-of-A/D-conversion determining unit 107 c, a charging controller108 c, and an image capturing controller 109 c may be provided in thepower feeder 25. In other words, an end-of-A/D-conversion determiningunit, a charging controller, and an image capturing controller may beprovided in at least either one of the console 28, the image capturingapparatus 22, the power feeder 25, and the electronic cassette 24 toallow the radiographic image capturing system 10 b to operate in thesame manner as the radiographic image capturing systems 10, 10 a. Theradiographic image capturing system 10 b may include another dedicatedconsole. If an end-of-A/D-conversion determining unit, a chargingcontroller, and an image capturing controller are provided in each of aplurality of apparatus, then the end-of-A/D-conversion determining unit,the charging controller, and the image capturing controller provided inany one of the apparatus may selectively be used under the control ofthe console 28, for example, whereas the functions of theend-of-A/D-conversion determining unit, the charging controller, and theimage capturing controller provided in the other apparatus may bedisabled.

Since the electronic cassette 24 incorporates the end-of-A/D-conversiondetermining unit 107, the charging controller 108, and the imagecapturing controller 109, the control function for permitting the powerfeeding after the A/D conversion may be added to an existingradiographic image capturing system simply by slightly modifying thecontrol program of the console 28.

With the radiographic image capturing systems 10, 10 a, 10 b,radiographic images used in a surgical operation are displayed by thedisplay device 26. However, the radiographic image capturing systems 10,10 a, 10 b may be used to capture ordinary radiographic images inapplications other than surgical operations. Similarly, the electroniccassette 24 is not limited to use in the operating room 12, but may beused in medical examinations or used by doctors when going the rounds inhospitals, for example.

As described in the above explanations of the first embodiment, thepower feeder 25 may be of any type insofar as it can supply electricpower contactlessly (wirelessly) to the electronic cassette 24. Forexample, the power feeder 25 may comprise components made of adielectric material for utilizing an electric field (electric fieldresonance) rather than the magnetic field (magnetic resonance), ratherthan the LC resonators 84, 88 and the detecting LC resonators 94, andhence may be other than the resonant wireless power feeder. Statedotherwise, the electric energy supplied from the power feeder 25 to theelectronic cassette 24 may be optical energy, thermal energy, or othertypes of energy.

In the radiographic image capturing systems 10, 10 a, 10 b, theradiation detector 40 housed in the electronic cassette 24 directlyconverts the dose of the applied radiation X into an electric signalwith the photoelectric conversion layer 51. However, the radiographicimage capturing systems may employ a radiation detector including ascintillator for converting the applied radiation X into visible lightand a solid-state detecting device such as of amorphous silicon (a-Si)or the like for converting the visible light into an electric signal(see Japanese Patent No. 3494683).

Alternatively, the radiographic image capturing systems may employ alight-conversion type radiation detector for acquiring radiographicimage information. The light-conversion type radiation detector operatesas follows: When radiation is applied to a matrix of solid-statedetecting devices, the solid-state detecting devices store anelectrostatic latent image depending on the dose of the appliedradiation. For reading the stored electrostatic latent image, readinglight is applied to the radiation detector, and the generated electriccurrent values are acquired as radiation image information. When erasinglight is applied to the radiation detector, radiographic imageinformation representing a residual electrostatic latent image is erasedfrom the radiation detector, which can thus be reused (see JapaneseLaid-Open Patent Publication No. 2000-105297).

Signals may be sent and received between the image capturing apparatus22, the power feeder 25, the display device 26, and the console 28 byway of wired communications. Wireless communications between theelectronic cassette 24 and external devices may be optical wirelesscommunications based on infrared rays rather than ordinary radio-wavecommunications.

FIG. 12 shows in perspective an electronic cassette 500 according to amodification of the electronic cassette 24.

As shown in FIG. 12, the electronic cassette 500 has guide lines 504drawn on the irradiated surface of a casing 502 as a reference mark foran image capturing area and an image capturing position. Using the guidelines 504, the subject to be imaged, such as the patient 14, can bepositioned with respect to the electronic cassette 500 and the range inwhich the radiation X is to be applied to the electronic cassette 500can be determined, for thereby recording radiographic image informationin an appropriate image capturing area of the electronic cassette 500.

The electronic cassette 500 also has a display unit 506 outside of theimage capturing area thereof for displaying various items of informationabout the electronic cassette 500. Specifically, the display unit 506displays ID information of the patient 14, whose radiation image isrecorded in the electronic cassette 500, the number of times that theelectronic cassette 500 has been used, an accumulated exposed dose, thecharged state (remaining power level) of the battery 44 housed in theelectronic cassette 500, image capturing conditions for radiographicimage information, and a positioning image representing the patient 14positioned with respect to the electronic cassette 500, etc. Theradiological technician can confirm the patient 14 based on the IDinformation displayed on the display unit 506, also confirm in advancethat the electronic cassette 500 is in a usable state, position thedesired area to be imaged of the patient 14 with respect to theelectronic cassette 500 based on the displayed positioning image, andcapture optimum radiographic image information in the electroniccassette 500.

The electronic cassette 500 includes a handle 508 to be gripped by theuser in order to handle and carry the cassette 500 with ease.

The cassette 500 also preferably has an input terminal 510 forconnection to an AC adapter, a USB (Universal Serial Bus) terminal 512,and a card slot 516 for receiving a memory card 514, all provided on aside wall of the casing of the electronic cassette 500.

When the charging function of the battery 44 housed in the electroniccassette 500 is low or when there is not enough time to charge thebattery 44, an AC adapter is connected to the input terminal 510 tosupply electric power from an external source for thereby making theelectronic cassette 500 immediately operable.

The USB terminal 512 or the card slot 516 can be used when theelectronic cassette 500 is unable to send and receive information to andfrom an external device such as the console 28 or the like by way ofwireless communications. Specifically, when a USB cable connected to theexternal device is connected to the USB terminal 512, the cassette 500can send and receive information to and from the external device by wayof wired communications through the USB terminal 512 and the USB cable.Alternatively, the memory card 514 is inserted into the card slot 516and necessary information from the cassette 500 is recorded into thememory card 514. Thereafter, the memory card 514 is disconnected fromthe card slot 516 and then connected to the external device to send theinformation to the external device.

FIG. 13 shows a cradle 518 for receiving the electronic cassette 24 andcharging the battery 44 housed in the electronic cassette 24. The cradle518 should preferably be positioned in the operating room 12 or adesired location in the hospital. The cradle 518 may not only be able tocharge the battery 44 with a contactless power feeder, not shown,similar to the above power feeder 25, but also have a wireless or wiredcommunication function to send and receive necessary information to andfrom an external device, such as the RIS 29, the HIS 33, the console 28,or the like. The information that is sent and received may includeradiation image information recorded in the electronic cassette 24loaded in the cradle 518.

The cradle 518 has a display unit 520 for displaying the charged stateof the battery 44 housed in the electronic cassette 24 and necessaryinformation including radiation image information acquired from theelectronic cassette 24.

A plurality of cradles 518 may be connected to a network, and chargedstates of the batteries 44 housed in the electronic cassettes 24 loadedin the respective cradles 518 may be retrieved through the network, sothat the user can confirm the locations of any electronic cassettes 24whose batteries 44 are sufficiently charged, based on the retrievedcharged states of the batteries 44.

FIG. 14 is a side elevational view, partly in block form, of aradiographic image capturing system 10 c according to a secondmodification of the radiographic image capturing system 10 shown in FIG.4.

The radiographic image capturing systems 10, 10 a, 10 b employ theelectronic cassette 24 as a radiation detecting apparatus for detectingthe applied radiation X and acquiring radiographic image information.The radiographic image capturing system 10 c shown in FIG. 14 employs,instead of the electronic cassette 24, a radiation detecting apparatus152 incorporated in an image capturing table 150 for the patient 14 tolie thereon, for capturing a radiographic image of the patient 14 whilethe patient 14 is lying on the image capturing table 150.

The radiation detecting apparatus 152 is substantially the same inconstruction as the electronic cassette 24 and incorporates therein theradiation detector 40, the battery 44, the wireless power receiver 49, acontroller 46 a, and the transceiver 48, which are housed in abox-shaped casing 154 made of a material that is permeable to theradiation X. The controller 46 a functions in substantially the samefashion as the cassette controller 46 of the electronic cassette 24, andhas the end-of-A/D-conversion determining unit 107, the chargingcontroller 108, and the image capturing controller 109.

A longitudinal rail 156 is mounted on a lower surface of the imagecapturing table 150. The radiation detecting apparatus 152 is movable toa desired position in the directions indicated by the arrow X(horizontal direction) along the rail 156 by a slider mechanism, notshown, mounted on the casing 154. Therefore, the radiation detectingapparatus 152 can be moved horizontally to a desired area to be imagedof the patient 14 lying on the image capturing table 150.

With the radiographic image capturing system 10 c, the radiationdetecting apparatus 152 is movable and incorporates the battery 44 andthe wireless power receiver 49, as with the electronic cassette 24.Consequently, no power cable needs to be connected to the radiationdetecting apparatus 152. The radiation detecting apparatus 152 can bemoved smoothly without being limited by the power cable and hence can behandled with ease. As with the radiographic image capturing systems 10,10 a, 10 b, the radiographic image capturing system 10 c is capable ofsuitably controlling the contactless (wireless) power feeding from thepower feeder 25 to the battery 44 and the image capturing by the imagecapturing apparatus 22 for thereby acquiring radiographic images of highquality.

As shown in FIG. 14, rollers 158 may be mounted on the lower ends oflegs of the image capturing table 150. Therefore, the image capturingtable 150 can easily be moved to a desired position. If necessary, therail 156 may be dispensed with, and the radiation detecting apparatus152 may be fixed to the image capturing table 150.

FIG. 15 is a side elevational view, partly in block form and crosssection, of a radiographic image capturing system 10 d according to athird modification of the radiographic image capturing system 10 shownin FIG. 4.

As with the radiographic image capturing system 10 c, the radiographicimage capturing system 10 d does not employ the electronic cassette 24,but includes a radiation detecting apparatus 164 detachably mounted on avertical post 162 fixed to a floor, not shown, and a wall 160, forcapturing a radiographic image of the patient 14 while the patient 14 isupstanding.

The radiation detecting apparatus 164 is substantially the same inconstruction as the electronic cassette 24 and the radiation detectingapparatus 152 and incorporates therein the radiation detector 40, thebattery 44, the wireless power receiver 49, the controller 46 a, and thetransceiver 48, which are housed in the box-shaped casing 154 made of amaterial that is permeable to the radiation X.

The radiation detecting apparatus 164, which functions as an upstandingimage capturing table, has a pair of vertically spaced upper and lowerhooks 166, 168 on a rear surface thereof which faces the post 162. Thepost 162 has a mounting recess 170 defined in a side surface thereofwhich faces the radiation detecting apparatus 164. A pair of verticallyspaced upper and lower shafts 172, 174 for engaging the respective hooks166, 168 are disposed in the mounting recess 170 and extend horizontallyin transverse directions (shoulder-width direction) of the patient 14.The lower hook 168 is pivotally supported on a pivot shaft 176 forupward swinging movement about the pivot shaft 176 as indicated by thetwo-dot-and-dash lines in FIG. 15. The lower hook 168 is normally biasedto turn downwardly by a spring mechanism, not shown, to stay inengagement with the lower shaft 174.

Since the hook 168 is swingably movable about the pivot shaft 176, thehooks 166, 168 can easily and reliably be brought into and out ofhooking engagement with the respective shafts 172, 174, or in otherwords, the radiation detecting apparatus 164 can easily and reliably bemounted on and removed from the post 162. The radiation detectingapparatus 164 mounted on the post 162 can be moved vertically in thedirections indicated by the arrows Y by a slide mechanism, not shown.

In FIG. 15, frames 178 are fixed to respective transverse ends of thecasing 154. The frames 178 are in the form of rods to be gripped by thepatient 14 when the patient 14 wants to take or keep a desired imagecapturing posture with respect to the radiation detecting apparatus 164.

With the image capturing system 10 d, the radiation detecting apparatus164 is removably mounted on and movable with respect to the post 162,and incorporates the battery 44 and the wireless power receiver 49 aswith the electronic cassette 24 and the radiation detecting apparatus152. Consequently, no power cable needs to be connected to the radiationdetecting apparatus 164. The radiation detecting apparatus 164 can bemoved and mounted and removed smoothly without being limited by thepower cable. As with the radiographic image capturing systems 10, 10 a,10 b, 10 c, the radiographic image capturing system 10 d is capable ofsuitably controlling the contactless (wireless) power feeding from thepower feeder 25 to the battery 44 and the image capturing by the imagecapturing apparatus 22 for thereby acquiring radiographic images of highquality.

FIG. 16 is a schematic view of a radiographic image capturing system 10e according to a fourth modification of the radiographic image capturingsystem 10, 10 b shown respectively in FIGS. 4, 11.

The radiographic image capturing system 10 e differs from theradiographic image capturing system 10, 10 b (see FIGS. 4 and 10) inthat the operation manager 102 has the end-of-A/D-conversion determiningunit 107 and the image capturing controller 109, and the console 28, theimage capturing apparatus 22 and the power feeder 25 have the chargingcontrollers 108 a, 108 b, 108 c, respectively.

In FIG. 16, constituent elements other than the operation manager 102,the end-of-A/D-conversion determining unit 107, the image capturingcontroller 109 in the electronic cassette 24, and the chargingcontrollers 108 a, 108 b, 108 c in the console 28, the image capturingapparatus 22 and the power feeder 25 are not illustrated.

In FIG. 16, the console 28, the image capturing apparatus 22 and thepower feeder 25 have the charging controllers 108 a, 108 b, 108 c,respectively. However, any one thereof may have a charging controller.That is, in the fourth modification, if the end-of-A/D-conversiondetermining unit, the image capturing controller and the chargingcontroller are assigned to at least two apparatus (two of the imagecapturing apparatus 22, the electronic cassette 24, the power feeder 25and the console 28), the same functions as the operation manager 102shown in FIG. 5 can be performed. Thus, the fourth modification is notlimited to an example of FIG. 16. For example, one apparatus may haveonly an end-of-A/D-conversion determining unit, while another apparatusmay have an image capturing controller and a charging controller.

In the image capturing system 10 e of FIG. 16, the end-of-A/D-conversiondetermining unit 107 and the image capturing controller 109 of theoperation manager 102 recognize a state (operation mode) of theelectronic cassette 24, and send a signal corresponding to the state tothe charging controllers 108 a, 108 b, 108 c. Then, the chargingcontrollers 108 a, 108 b, 108 c determine the most appropriate powerfeeding state based on the operation mode (the sent signal), andgenerates signals corresponding to the determined most appropriate powerfeeding state.

The image capturing system 10 e according to the fourth modification canobtain the same advantageous effects as the image capturing system 10 ofthe first embodiment and the image capturing system 10 b of the firstmodification.

FIG. 17 is a schematic view of a radiographic image capturing system 10f according to a fifth modification of the radiographic image capturingsystem 10 shown in FIG. 4.

The image capturing system 10 f differs from the image capturing system10 (see FIGS. 4 and 5) according to the first embodiment in that thefeeding controller 86 of the power feeder 25 has a mutual inductancedetecting unit 200, and the wireless power receiver 49 has a relay 202.In FIG. 17, constituent elements other than the LC resonator 84 and thepower feeding controller 86 of the power feeder 25, the battery 44 ofthe electronic cassette 24 and the wireless power receiver 49 are notillustrated.

In an example thereof, the LC resonator 84 of the power feeder 25comprises an LC parallel resonant circuit having a coil 204 and acapacitor 206 that are connected together in parallel with each other,while the LC resonator 88 or the detecting LC resonator 94 of theelectronic cassette 24 comprises an LC parallel resonant circuit havinga coil 208 and a capacitor 210 that are connected together in parallelwith each other. The relay 202 comprises an operation coil 212 to whichthe charging controller 108 supplies a signal (electric current), and acontact-type switch 214 for performing ON-OFF action in response toexcitation of the operation coil 212 by the electric current. The switch214 has an end connected to the coil 208 and the capacitor 210, and theother end connected to the charging circuit 90.

When the charging controller 108 determines charging of the battery 44and then applies electric current to the operation coil 212, theoperation coil 212 generates magnetic flux based on the electriccurrent, and magnetizes an electromagnet (not shown). As a result, theelectromagnet attracts a piece of iron of the switch 214 to switch froman OFF-state to an ON-state. Thus, contactless power feeding by thepower feeder 25 to the battery 44 is enabled. On the other hand, whilethe contactless power feeding is being performed, the coil 204 of the LCresonator 84 and the coil 208 of the LC resonator 88 or the detecting LCresonator 94 are magnetically-coupled to each other through a mutualinductance mi.

In this state, if the charging controller 108 determines stoppage(inhibition) of charging the battery 44 to stop energization of theoperation coil 212, generation of magnetic flux by the operation coil212 is halted. Accordingly, the piece of iron is separated away from theelectromagnet, and the switch 214 is brought into an OFF-state. As aresult, the electric connection between the coil 208, the chargingcircuit 90 and the battery 44 is cut off, and then the mutual inductancemi between the coil 204 and the coil 208 changes abruptly.

The mutual inductance detecting unit 200 detects electric currentflowing through the coil 204. When the magnitude of the electric currentchanges temporally abruptly, the mutual inductance detecting unit 200judges that the mutual inductance mi has changed abruptly due toswitching of the switch 214 from an ON-state to an OFF-state.

When the mutual inductance detecting unit 200 detects an abrupt changeof the mutual inductance mi, the feeding controller 86 judges that thecharging controller 108 has determined stoppage (inhibition) of chargingthe battery 44. Then, the feeding controller 86 stops supply of electricenergy (high-frequency electric power) to the LC resonator 84.

In the image capturing system 10 f according to the fifth modification,even if the feeding inhibition signal is not supplied for some reasons,the power feeder 25 can stop contactless power feeding based ondetection of an abrupt temporal change of the mutual inductance mi bythe mutual inductance detecting unit 200, thereby performing feedingcontrol of the battery 44 accurately and reliably. Thus, the powerfeeder 25 can judge, on its own, whether power feeding to the battery 44should be inhibited or not, even without supply of the feedinginhibition signal from the charging controller 108.

In the above explanations, if it is judged that the remaining powerlevel of the battery 44 is sufficient, then a feeding inhibition signaland an image capturing permission signal are transmitted to performcharging inhibition control arising from starting of image capturing.When the remaining power level of the battery 44 is sufficient, thefollowing charging inhibition control may be performed instead of theabove charging inhibition control. That is, a power switch (not shown)is provided on a side surface of the electronic cassette 24. A doctor 18or a technician operates the power switch to start image-capturing, andthen the image capturing permission signal and the feeding inhibitionsignal are transmitted to perform charging inhibition control.

With the radiographic image capturing systems 10, 10 a, 10 b, 10 c, 10d, 10 f, the electronic cassette 24 and the radiation detectingapparatus 152, 164 are movable. Even when the electronic cassette 24 andthe radiation detecting apparatus 152, 164 are set in a desired imagecapturing position, they can easily be supplied with electric power bythe power feeder 25. Since the electronic cassette 24 and the radiationdetecting apparatus 152, 164 have the end-of-A/D-conversion determiningunit, the charging controller, and the image capturing controller, thecontactless (wireless) power feeding is not carried out at least untilthe A/D conversion of the detected radiographic image information isfinished. Consequently, it is possible to capture radiographic images ofhigh quality without being adversely affected by noise caused by thecontactless (wireless) power feeding, and also to quickly charge thebattery 44 while no radiographic images are being captured, i.e., afterthe image capturing process has been finished.

Although certain preferred embodiments of the present invention havebeen shown and described in detail, it should be understood that variouschanges and modifications may be made therein without departing from thescope of the appended claims.

1. A radiation detecting apparatus comprising: a radiation detector fordetecting radiation applied from an external image capturing apparatusand transmitted through a subject; a contactless power receiver forreceiving electric power supplied contactlessly from an externalcontactless power feeder and supplying the received electric power to apower supply; an A/D converter for performing an A/D conversion toconvert analog radiographic image information which has been generatedbased on the radiation applied to the radiation detector, into digitalradiographic image information; an end-of-A/D-conversion determiningunit for determining whether the A/D conversion is finished or not; anda charging controller for stopping the contactless power feeder fromsupplying electric power contactlessly after the external imagecapturing apparatus has started to capture a radiographic image untilthe end-of-A/D-conversion determining unit judges that the A/Dconversion is finished.
 2. A radiation detecting apparatus according toclaim 1, wherein the charging controller generates a feeding inhibitionsignal to inhibit the contactless power feeder from supplying electricpower contactlessly before the external image capturing apparatus startsto capture a radiographic image.
 3. A radiation detecting apparatusaccording to claim 1, wherein the charging controller generates afeeding permission signal to permit the contactless power feeder tosupply electric power contactlessly if the end-of-A/D-conversiondetermining unit judges that the A/D conversion is finished.
 4. Aradiation detecting apparatus according to claim 1, further comprising:an image memory for storing the digital radiographic image informationconverted by the A/D converter; wherein the end-of-A/D-conversiondetermining unit judges that the A/D conversion is finished when thedigital radiographic image information is stored in the image memory. 5.A radiation detecting apparatus according to claim 2, furthercomprising: an image capturing controller for generating an imagecapturing permission signal to permit the external image capturingapparatus to capture a radiographic image when the charging controllergenerates the feeding inhibition signal.
 6. A radiographic imagecapturing system comprising: an image capturing apparatus for applyingradiation to a subject; a radiation detecting apparatus including aradiation detector for detecting the radiation transmitted through thesubject, an A/D converter for performing an A/D conversion to convertanalog radiographic image information which has been generated based onthe radiation applied to the radiation detector, into digitalradiographic image information, and a power supply for supplyingelectric power to the radiation detector; a contactless power feederdisposed in the radiation detecting apparatus, for supplying electricpower contactlessly to a contactless power receiver which supplieselectric power to the power supply; a controller for controlling theimage capturing apparatus, the radiation detecting apparatus, and thecontactless power feeder; an end-of-A/D-conversion determining unit fordetermining whether the A/D conversion is finished or not; and acharging controller for stopping the contactless power feeder fromsupplying electric power contactlessly after the image capturingapparatus has started to capture a radiographic image until theend-of-A/D-conversion determining unit judges that the A/D conversion isfinished.
 7. A radiographic image capturing system according to claim 6,wherein the charging controller generates a feeding inhibition signal toinhibit the contactless power feeder from supplying electric powercontactlessly before the image capturing apparatus starts to capture aradiographic image.
 8. A radiographic image capturing system accordingto claim 6, wherein the charging controller generates a feedingpermission signal to permit the contactless power feeder to supplyelectric power contactlessly if the end-of-A/D-conversion determiningunit judges that the A/D conversion is finished.
 9. A radiographic imagecapturing system according to claim 6, wherein the radiation detectingapparatus further comprises an image memory for storing the digitalradiographic image information converted by the A/D converter; and theend-of-A/D-conversion determining unit judges that the A/D conversion isfinished when the digital radiographic image information is stored inthe image memory.
 10. A radiographic image capturing system according toclaim 7, further comprising: an image capturing controller forgenerating an image capturing permission signal to permit the imagecapturing apparatus to capture a radiographic image when the chargingcontroller generates the feeding inhibition signal.
 11. A radiographicimage capturing system according to claim 6, which is connected to aninformation management system for storing the number of times that thesubject is to be imaged; wherein the end-of-A/D-conversion determiningunit determines whether the A/D conversion is finished or not after asmany radiographic images of the subject as the number of times that thesubject is to be imaged which is stored in the information managementsystem have been captured.
 12. A radiographic image capturing systemaccording to claim 8, wherein the charging controller generates thefeeding permission signal when the image capturing apparatus stopsapplying the radiation and when the end-of-A/D-conversion determiningunit judges that the A/D conversion is finished.
 13. A radiographicimage capturing system according to claim 8, wherein the chargingcontroller generates the feeding permission signal upon elapse of agiven time after the end-of-A/D-conversion determining unit has judgedthat the A/D conversion is finished.
 14. A radiographic image capturingsystem according to claim 8, wherein the charging controller generatesthe feeding permission signal upon elapse of a given time after theimage capturing apparatus has started applying the radiation.
 15. Amethod of capturing a radiographic image of a subject by applyingradiation to the subject, detecting the radiation with a radiationdetector of a radiation detecting apparatus, and converting the detectedradiation into radiographic image information with the radiationdetector, comprising the steps of: supplying electric powercontactlessly to a power supply of the radiation detecting apparatus;and stopping supplying electric power contactlessly to the power supplyafter image-capturing by the radiation has been started at least untilan A/D conversion of the radiographic image information detected by theradiation detector is finished.